The present invention relates to a high pressure hydraulic distributor.
More precisely, it relates to a hydraulic distributor of the type comprising:
a body itself having an inlet duct having connection means to a first source of hydraulic fluid under pressure, a first outlet duct having connection means to utilisation means of such a fluid, a second outlet duct having connection means to a fluid reservoir,
first distributor means interposed between the inlet duct and the first outlet duct inside the body for, at will, establishing a fluid feed circuit from the inlet duct towards the first outlet duct or closing this circuit,
second distributor means, interposed between the first inlet duct and the second outlet duct inside the body for, at will, establishing a fluid return circuit from the first outlet duct to the second outlet duct or closing this circuit,
control means for the first and second distributor means for, at will, establishing one of the said circuits and closing the other or closing these two circuits simultaneously,
and it particularly concerns such distributors intended for high pressure applications, that is to say for example when the utilisation means are constituted by hydraulic jacks carrying out the functions of handling loads or displacing members, on mobile mechanical handling machines or on agricultural machines.
The distributors of this type, having single-acting jacks, are particularly appreciated insofar that they permit limiting the powering of the source of hydraulic fluid under pressure to operations for which the jacks are active, which correspond to the establishment of the feed circuit; for operations for which the jack is passive, which correspond to the establishment of the return circuit, on the contrary, the source of hydraulic fluid is not powered, this takes on a particular importance in the case of mobile electric machines powered from a bank of accumulators powering in particular an electric drive motor of a pump constituting the source of hydraulic fluid, insofar as this battery is economised.
Nevertheless, the practical embodiment of distributors of this type is difficult since particularly in the interests of safety, it is desirable that single-acting jacks controlled by such distributors have stable positions other than their passive end of stroke position; in fact, since the jacks are used in such other positions, any leakage particularly inside the distributor consititutes an obstacle to such stability.